1. Field of the Invention
The present invention generally relates to a de-interlacing method, in particular, to an edge detection method of the de-interlacing method.
2. Description of Related Art
One way to increase the resolution of television images is to convert an interlaced image into a progressive-scanned image. In a de-interlacing processing, in order to increase the resolution and eliminate jagged rims of inclined edges of the image, an inclined interpolation processing is always performed on an inclined line portion in the image.
In the prior art, for example, an adaptive diagonal interpolation for image resolution enhancement is disclosed in U.S. Pat. No. 6,133,957. In such method, the difference between the pixels at different angles within a certain range is calculated. Finally, the angle corresponding to the smallest difference is adapted as the slope of the inclined line, and the interpolation is performed with the slope.
However, the above method cannot accurately obtain the positions of the inclined line of the image or precisely calculate the slope (angle) of the inclined line. In the case that the position or angle is not correct, the jags in the image cannot be eliminated and the resolution cannot be effectively enhanced. Even worse, the interpolation effect is degraded, and random line or noise is generated on the image.
Therefore, it is in urgent need of a simple and accurate method for detecting an inclined edge and its inclined angle in an image, so as to enhance the resolution of display image.